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Experimental data for C6H8 (1,4-Cyclohexadiene)

22 02 02 11 45
Other names
1,4-Cyclohexadiene; 1,4-Dihydrobenzene; Cyclohexa-1,4-diene; cyclohexadiene;
INChI INChIKey SMILES IUPAC name
InChI=1S/C6H8/c1-2-4-6-5-3-1/h1-2,5-6H,3-4H2 UVJHQYIOXKWHFD-UHFFFAOYSA-N C1=CCC=CC1 Cyclohexa-1,4-diene
State Conformation
1Ag C2V
Enthalpy of formation (Hfg), Entropy, Integrated heat capacity (0 K to 298.15 K) (HH), Heat Capacity (Cp)
Property Value Uncertainty units Reference Comment
Hfg(298.15K) enthalpy of formation 109.00   kJ mol-1 TRC
Hfg(0K) enthalpy of formation 132.60   kJ mol-1 TRC
Entropy (298.15K) entropy 296.34   J K-1 mol-1 TRC
Integrated Heat Capacity (0 to 298.15K) integrated heat capacity 16.56   kJ mol-1 TRC
Heat Capacity (298.15K) heat capacity 94.10   J K-1 mol-1 webbook
Information can also be found for this species in the NIST Chemistry Webbook
Vibrational levels (cm-1) vibrations
Mode Number Symmetry Frequency Intensity Comment Description
Fundamental(cm-1) Harmonic(cm-1) Reference (km mol-1) unc. Reference
1 Ag 3032   1998Moo/Kwo:265      
2 Ag 2822   1998Moo/Kwo:265      
3 Ag 1680   1998Moo/Kwo:265      
4 Ag 1426   1998Moo/Kwo:265      
5 Ag 1159   1998Moo/Kwo:265      
6 Ag 854   1998Moo/Kwo:265      
7 Ag 530   1998Moo/Kwo:265      
8 Au 1100   1998Moo/Kwo:265      
9 Au 1000   1998Moo/Kwo:265      
10 Au     1998Moo/Kwo:265       questionable (listed as 250)
11 B1g 3019   1998Moo/Kwo:265      
12 B1g 1377   1998Moo/Kwo:265      
13 B1g 1358   1998Moo/Kwo:265      
14 B1g            
15 B1g 574   1998Moo/Kwo:265      
16 B1u 2875   1998Moo/Kwo:265      
17 B1u 956   1998Moo/Kwo:265      
18 B1u 622   1998Moo/Kwo:265      
19 B1u 108   1998Moo/Kwo:265      
20 B2g 2877   1998Moo/Kwo:265      
21 B2g            
22 B2g 985   1998Moo/Kwo:265      
23 B2g 403   1998Moo/Kwo:265      
24 B2u 3130   1998Moo/Kwo:265      
25 B2u 1639   1998Moo/Kwo:265      
26 B2u 1197   1998Moo/Kwo:265      
27 B2u 1193   1998Moo/Kwo:265      
28 B2u 956   1998Moo/Kwo:265      
29 B3g            
30 B3g 706   1998Moo/Kwo:265      
31 B3u 3019   1998Moo/Kwo:265      
32 B3u 2825   1998Moo/Kwo:265      
33 B3u 1430   1998Moo/Kwo:265      
34 B3u 1405   1998Moo/Kwo:265      
35 B3u 1035   1998Moo/Kwo:265      
36 B3u 887   1998Moo/Kwo:265      

vibrational zero-point energy: 24089.5 cm-1 (from fundamental vibrations)
Calculated vibrational frequencies for C6H8 (1,4-Cyclohexadiene).
Gas-phase IR spectra can be found in the NIST Chemistry Webbook here.
Rotational Constants (cm-1) rotational constants
See section I.F.4 to change rotational constant units
A B C reference comment
       

Calculated rotational constants for C6H8 (1,4-Cyclohexadiene).
Product of moments of inertia moments of inertia
amu3Å6   0gm3 cm6
Geometric Data
picture of 1,4-Cyclohexadiene

Point Group D2h


Internal coordinates
distances (r) in Å, angles (a) in degrees, dihedrals (d) in degrees
Description Value unc. Connectivity Reference Comment
Atom 1 Atom 2 Atom 3 Atom 4
rCC 1.347   3 4 1976Hellwege(II/7)
rCC 1.511   1 4 1976Hellwege(II/7)
rCH 1.100   1 11 1976Hellwege(II/7) weighted average
aCCC 123 1 4 3 1976Hellwege(II/7)

Cartesians
Atom x (Å) y (Å) z (Å)

Atom - Atom Distances bond lengths
Distances in Å
 

Calculated geometries for C6H8 (1,4-Cyclohexadiene).

Bond descriptions


Examples: C-C single bond, C=C, double bond, C#C triple bond, C:C aromatic bond
Bond Type Count
H-C 8
C-C 4
C=C 2

Connectivity
Atom 1 Atom 2
C1 C4
C1 C6
C1 H11
C1 H13
C2 C3
C2 C5
C2 H12
C2 H14
C3 C4
C3 H10
C4 H9
C5 C6
C5 H8
C6 H7
Electronic energy levels (cm-1)
Energy (cm-1) Degeneracy reference description
0 1   1Ag

Ionization Energies (eV)
Ionization Energy I.E. unc. vertical I.E. v.I.E. unc. reference
8.820   8.820   webbook
Dipole, Quadrupole and Polarizability
Electric dipole moment dipole
State Config State description Conf description Exp. min. Dipole (Debye) Reference comment Point Group Components
x y z total dipole quadrupole
1 1 1Ag C2v True           D2h 0 2
Experimental dipole measurement abbreviations: MW microwave; DT Dielectric with Temperature variation; DR Indirect (usually an upper limit); MB Molecular beam
Calculated electric dipole moments for C6H8 (1,4-Cyclohexadiene).
Electric quadrupole moment quadrupole
State Config State description Conf description Exp. min. Quadrupole (D Å) Reference comment Point Group Components
xx yy zz dipole quadrupole
1 1 1Ag C2v True       D2h 0 2

Calculated electric quadrupole moments for C6H8 (1,4-Cyclohexadiene).
References
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squib reference DOI
1976Hellwege(II/7) Hellwege, KH and AM Hellwege (ed.). Landolt-Bornstein: Group II: Atomic and Molecular Physics Volume 7: Structure Data of Free Polyatomic Molecules. Springer-Verlag. Berlin. 1976.  
1998Moo/Kwo:265 Moon, Kwon, and Choo. Vibrational spectra and conformations of 1,4-cyclohexadiene and its oxygen analogues: ab initio and density functional calculations. J. Mol. Struct. Vol. 470. pgs. 265-275. 10.1016/S0022-2860(98)00391-3
TRC Frenkel, M; Marsh, K.N.; Wilhoit, R.C.; Kabo, G.J.; Roganov, G.N.,Thermodynamics of Organic Compounds in the Gas State,Thermodynamics Research Center, College Station, TX, 1994  
webbook NIST Chemistry Webbook (http://webbook.nist.gov/chemistry) 10.18434/T4D303

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